Apparatus for generating gears



Aug. 17, 1954 R. A. M CALLUM APPARATUS FOR GENERATING GEARS 4Sheets-Sheet 1 Filed Dec. 6, 1949 Aug. 17, 1954 R. A. M CALLUM APPARATUSFOR GENERATING GEARS 4 Sheets-Sheet 2 Filed Dec. 6. 1949 iii BYQQMRP @ow mix A TORNEY 1954 R. A. MCCALLUM APPARATUS FOR GENERATING GEARS 4Sheets-Sheet 3 Filed Dec. 6, 1949 A Tree/v0 INVENTOR. Qogerifl, M'Ca/Zum Aug. 17, 1954 R. A. MCCALLUM APPARATUS FOR GENERATING GEARS 4Sheets-Sheet 4 Filed Dec. 6, 1949 Patented Aug. 17, 1954 2,686,457APPARATUS FOR GENERATING GEARS Robert A. McCallum, Clarendon Hills,Ill., as-

signor to Goodman Manufacturing (Company, Chicago, 111., a corporationof Illinois Application December 6, 1949, Serial No. 131,313

4 Claims.

This invention relates to improvements in apparatus for generatinggears, and relates particularly to improvements in machines forgenerating varying speed gears having varying curvilinear pitch andvarying pitch radius, or for generating varying speed gears havingconstant curvilinear pitch and varying pitch radius.

In an application of William W. Sloane, Serial No. 123,581, filedOctober 26, 1949, Patent No. 2,565,528, August 28, 1951, forImprovements in Mechanical Miners, there is shown varying speed gearingfor imparting changing speed of a pair of cranks or shafts relative toeach other, the gears so shown. being characterized by beingeccentrically mounted and having constant curvilinear pitch and avarying pitch radius. In an application of William W. Sloane, Serial No.702,724, filed October 11, 1946, Patent No. 2,585,971, February 19,1952, for Improvements in Gearing, there is disclosed a novel form ofvarying speed gearing in which the speed variations are attained bymodifying the gear teeth so that the matching pinion will contact thegear teeth at varying points with respect to the tips and roots of thegears and pinions.

Such gears may be manufactured by apparatus as disclosed in Hlinskyapplication Serial No. 711,745, filed November 22, 1946, Patent No.2,602,374, July 8, 1952, Improvements in Apparatus for Producing VaryingSpeed Gearing, or in Holstein application Serial No. 733,839, filedMarch 11, 1947, Patent No. 2,616,336, November 4, 1952, for Methods andApparatus for Producing Varying Speed Gearing, or in Millhuiiapplication Serial No. 122,045, filed October 18, 1949, Patent No.2,649,716, August 25, 1953, for Improvements in Apparatus for GeneratingGears.

According to the present invention it is possible to fabricate a varyingspeed gear having constant curvilinear pitch and varying pitch radius ora varying speed gear having varying curvilinear pitch and varying pitchradius. According to the present invention it is also possible tofabricate a varying speed gear having constant curvilinear pitch andadapted to run eccentrically with a mating eccentrically mounted gear,such a gear being fabricated by means of a pinion-shaped cutter which ismounted concentrically and of a size different from the mating eccentricgear.

With the foregoing considerations in mind it is a principal object ofthe invention to afford apparatus for fabricatin varying speed gearingby a gear shaper employing a pinion-shaped cutter for shaping of afinished gear from a gear blank.

Another object is to provide apparatus for use 2 with a gear shaper soconstructed and arranged as to enable a varying speed gear to befabricated with a standard pinion-shaped cutter, and to support a gearblank by means of such apparatus for both rotative and radial movementthereof with respect to the work spindle of the gear shaper, suchrotative and radial movement providing for proper working distance withrespect to the pinion-shaped cutter.

Still another object is to afford apparatus for use with a gear shaperto fabricate a varying speed gear, such apparatus being characterized bya pair of cams cooperating with cam followers for advancing or retardinthe gear blank with respect to the work spindle and for moving the gearblank radially with respect to the work spindle to the end that astandard reciprocating and rotating pinion-shaped cutter may be employedto operate on the gear blank and produce a, varying speed gear asdesired.

Yet another object comprehends the provision of a plurality of floatingcams for moving a gear blank to be acted upon by a shaping cutter in agear shaper, the two floating cams being connected together but havingrotative movement relative to each other, one of the cams being adaptedto cooperate with a stationary cam follower to move both of the floatingcams radially, and the other of the cams being held against rotation andadapted to cooperate with a moving cam follower connected to the gearblank to advance or retard the gear blank rotatively while the gearblank is also moved radially through the instrumentality of the firstmentioned cam.

Other objects and important features of the invention will be apparentfrom a study of the following description taken together with thedrawings which illustrate an embodiment that the invention has assumedin practice, and what is now considered to be the best mode of applyingthe principles thereof. While the invention is described in terms ofwhat is considered a preferred embodiment thereof, its scope is notintended to be limited in terms of the embodiment shown nor otherwisethan by the terms of the subjoined claims.

In the drawings:

Fig. 1 is a plan View of a gear shaping fixture embodied in the presentinvention;

Fig. 2 is a transverse section through the fixture of Fig. 1, takenalong the line 2-2 in Fig. 1 and looking in the direction of the arrows,and showin in phantom outline a pinion-shaped cutter adapted to act upona gear blank, shown also in phantom outline, mounted on the fixture;

Fig. 3 is a plan view of a cam for controlling the advancing andretarding rotative movement 3 of the gear blank shown in Fig. 2, takenon a plane indicated by the line 3-3 of Fig. 2 and looking in thedirection of the arrows;

Fig. 4 is a plan view taken along the line 4-4 of Fig. 2 looking in thedirection of the arrows, and showing details of a cam for controllingthe radial movement of the gear blank shown in Fig. 2;

Fig. 5 is a section taken along the line 5-5 of Fig. 4 looking in thedirection of the arrows;

Fig. 6 is a plan view of a coupling member locking in the direction ofthe arrows 66 of Fig. 2; and

Fig. 7 is a section taken along the line l-! of Fig. 6.

Referring now to the drawings, the gear shaping fixture according to thepresent invention is shown as applied to a machine tool gear shaper.Such a shaper may include a cylindrical rotating work spindle H adaptedto turn at constant speed in a bed I2. The work spindle cooperates withmechanism to be described, to impart both rotative and radial movementto a gear blank is which is acted upon by a reciprocating pinionshapedcutter l4 which also rotates at a constant speed at a fixed ratio withrespect to the work spindle l, to generate a gear from the gear blank l3having varying speed characteristics as determined by the curvilinearpitch and the pitch radius of the finished gear.

The cylindrical work spindle I is provided with an end closure plate Itwhich is held to the work spindle by socket head screws H. The closureplate 16 is formed with a concentric bushed spindle M3 to turn in abushing plate l9 held against rotation by an arm 2| adjustable inposition with the bushing plate l9 by adjusting screws 22 which bearagainst a lug 23 secured to the bed l2.

The bushing H3 is held in position by socket head screws 24 which threadinto a load transmitting member 26 having radially extending keys 21which cooperate with keyways 28 formed in an Oldham-type coupling 29which rests upon the load transmitting member 26.

The coupling 29 is provided with radially extending keyways 3|, whichare spaced angularly with respect to the keyways 28, and which cooperatewith radially extending keys 32 formed integrally with a cam 33. Asshown in Figure 1,

the cam 33 is adapted to cooperate with a stationary cam follower 34journaled on a pin 35 which is pressed in a support 3'! secured byscrews 38 to the bushing plate ill. The cam 33 is provided with aspindle 391 which is adapted to rotate with respect to a bushed cam 43which is held against rotation but adapted to have radial movement withrespect to the work spindle l l by means of a sliding gibbed connection42 to a pedestal 43. As shown with particular reference to Fig. 1, thepedestal 43 is held by a plurality of bolts 44, 44 to the bushing plate|9. The cam 4| is likewise provided with a sliding key fitted to thesupport 31 as at 48. The cam 33 and the cam 4| are held together by adrag arm 41 by means of a plurality of liner pins 48 and socket headscrews 49.

It will be apparent from the foregoing description that both rotativeand translative movement of the cam 33 and the drag arm 41 will beafforded by means of the coupling 29, and that the cam 4| will have onlya translative or radial movement while being held against rotationthrough the medium of the keys 42 and 46.

In order to insure that the cam 33 will be forced to bear against thecam roller 34 at all times, and

that the cam 4| will likewise be prevented from having unintendedmovement, as might be cccasioned by the failure of the cam roller 34 toengage the cam 33, the pedestal 43 provides a sliding gibbed connectionwith a pair of yoke arms 5| which are bolted as at 52 to the undersideof the cam 4|. As seen in Figure 4., the left ends of the yoke arms 5|are adapted to move in gibs 53 formed in the pedestal 43, and the rightends thereof, as seen in Fig. 4, are also adapted to move in gibs 54formed in the extremities of the support 31. The yoke arms 5| are eachprovided with a stud 5B which supports a strap 5! adapted to abut thesupport 31. As shown in Fig. 4, each stud 56 is encircled by a spring 58adjusted in tension by adjusting nuts 5i} threaded thereto. t will beapparent that the load in the spring 53 constantly tends to move the cam4| to the right together with the cam 33 so that the cam 33 will be inengagement at all times with the cam follower 34.

A spindle 48 is adapted to turn freely within the spindle 39 and is heldagainst endwise movement with respect thereto by means of a washer 61and a castellated nut 52, which is held in posi tion by a cotter key 63.The spindle 43 is provided with a cap 64 which fits within a recess 65of a gear blank support 81. The spindle 4i? and the gear support 61 areheld together by a plurality of socket head screws 68. The gear blanksupport 61 is additionally supported on a split ring 69 which in turnrests upon the cam 4 The gear blank support 61 is held to the split ring69 by means of a plurality of socket head screws The split ring 62defines an opening 12 for the drag arm 47, which extends beyond theperipheral limits of the cam 4| and engages a roller 13 which freelyturns on a pin E4 mounted on the end ora cam follower arm 16, which ishinged as at 71 to an arm '18 formed integrally with the split supportring 69. The pin '14 also provides a journal for a cam roller 19 whichengages the periphery of the cam 4|.

In order to insure that the drag arm 41 is in contact at all times withthe roller 13, a spring 8| is provided, one end of which abuts the splitring 59 as at 82, the other end of which abuts the drag arm 41 as at 83.It may be noted that the drag arm 4'! is provided with a flat surface 84which is so disposed with the instantaneous center of rotation of thearm 41 that a slight amount of wedging action is provided between thesurface 84 and the cam roller 13, so that the cam roller 73 isconstantly forced against the periphery of the cam 4|.

It will be noted that as the drag arm ill rotates with the cam 33, andmaintains the cam roller JS in firm contact with the periphery of thecam 4 l the change in contour of the cam 4| will cause the support 89 toretard and advance rotationally with respect to the drag arm 4'! and thecam 33, and since the split support 69 is connected to the gear blanksupport 61, it likewise will be advanced or retarded rotationally withrespect to the arm 41 and the cam 33.

The gear blank support 5'? is provided with a stud 86, which isconcentric with a locating boss 8? held to the gear blank support 5? bysocket head screws 88. The gear blank i3 is thus held in position by thelocating boss 8'1, the pin 86. and a retaining washer 89., which is heldin firm engagement with the gear blank l3 by means of a spanner nut 3|threaded to the stud 26. In order to locate the gear blank it properlythe gear blank support 51 is provided with a recess 92 for a locatingpin 93 adapted to extend into a locating hole 94 formed in the gearblank l3. It may be noted from the foregoing description that the gearblank 13 is adapted tohave both radial movement with respect to the workspindle l l and rotational movement at rates which vary with respect tothe speed of rotation of the work spindle I i. Through the medium of thecoupling 29 and the contour of the cam 33 translative movement will beafforded to both the drag arm i! and the cam 4|. However, since the cam41 is held against rotation, it has only the translative or radialmovement afiorded by the cam 33 and the coupling 29, but the drag arm4'! will have rotative movement corresponding to the rotative movementof the work spindle H. The drag arm 4'! constantly applies rotativemovement against the idler roller 73, but the amount of that movementreflected into the rotative movement of the gear blank support 6?, isaffected by the contour of the cam 4|, and according to the contour ofthe cam 4| the gear blank support 61 will be advanced or retarded.

From the foregoing description it will be apparent that it is possibleto generate an eccentric gear by means of a gear shaper employing astandard shape pinion cutter, and to provide in the finished gear bothvarying pitch radius and varying curvilinear pitch, as desired.According to the contour of the cams 33 and 4| the gears generated bythe fixture according to the present invention may be made to run with apinion of different size from the pinion-shaped cutter employed in theshaping operation.

While the invention has been described in terms of a preferredembodiment thereof, its scope is not intended tobe limited in terms ofthe embodiment shown nor otherwise than by the terms of the subjoinedclaims.

I claim as my invention:

1. In a gear shaper for generating a varying speed gear by reciprocatingmovement of a rotating pinion-shaped cutter with respect to a rotatablydriven gear blank, a work spindle driven at a fixed speed relative tosaid rotating cutter, a support for said gear blank adapted to have bothrotative and radial movement with respect to said work spindle inaccordance with the curvilinear pitch and the pitch radius of thefinished gear, means for advancin or retarding the rotative movement ofsaid support with respect tosaid work spindle in accordance with thecurvilinear pitch of the finished gear, and means for moving the supportradially with respect to said work spindle in accordance with the pitchradius of the finished gear comprising a cam adapted to rotate with saidwork spindle, and a stationary member in contact with said cam foreffecting radial movement of said cam and said gear support.

2. In a gear shaper for generating a varying speed gear by reciprocatingmovement of a rotating pinion-shaped cutter with respect to a rotatablydriven gear blank, a work spindle driven at a fixed speed relative tosaid rotating cutter, a support for said gear blank adapted to have bothrotative and radial movement with respect to said work spindle inaccordance With the curvilinear pitch and the pitch radius of thefinished gear, means for advancing or retarding the rotative movement ofsaid support with respect to said work spindle in accordance with thecurvilinear pitch of the finished gear, and means for moving the supportradially with respect to said work spindle in accordance with the pitchradius of the finished gear comprising a cam adapted to rotate with saidWork spindle, and a stationary cam follower for moving said cam radiallywith respect to said work spindle, and coupling means between said workspindle and said cam comprising a load transmitting memher having aradially extending load transmitting connection with said work spindleand having a radially extending load transmitting con,- nection withsaid cam, said first and second named radially extending loadtransmitting connections being spaced angularly with respect to eachother.

3. In a gear shaper for generating a varying speed gear by reciprocatingmovement of a rotating pinion-shaped cutter with respect to a rotatablydriven gear blank, a work spindle driven at a fixed speed relativetosaid rotating cutter, a support for said gear blank adapted to haveboth rotative and radial movement with respect to said work spindle inaccordance with the curvilinear pitch and the pitch radius of thefinished gear, means for moving the support radially with respect tosaid work spindle in accordance iwth the pitch radius of the finishedgear, and means for advancing or retarding the rotative movement of saidsupport with respect to said work spindle inaccordance with thecurvilinear pitch of the finished gear comprising a cam held againstrotation and adapted to move radially with the support, and a camfollower cooperating with said cam and having an operative connectionwith said support.

4. In a gear shaper for generating a varying speed gear by reciprocatingmovement of a 1'0- tating pinion-shaped cutter with respect toarotatably driven gear blank, a work spindle driven at a fixed speedrelative to said rotating cutter, a support for said gear blank adaptedto have both rotative and radial movement with respect to said workspindle in accordance with the curvilinear pitch and the pitch radius ofthe finished gear, means comprising a cam adapted to rotate with saidwork spindle and to have radial movement with respect thereto for movingsaid work support radially with respect to said work spindle inaccordance with the pitch radius of the finished gear, coupling meansbetween said work spindle and said cam compris ing a load transmittingmember having a radially extending load transmitting connection withsaid work spindle and having a radially extending load transmittingconnection with said cam, said first and second named radially extendingload transmitting connections being spaced angularly with respect toeach other, and means for advancing or retarding the rotative movementof said support with respect to said work spindle in accordance with thecurvilinear pitch of the finished gear comprising a cam held againstrotation and a cam follower cooperating with said cam and having anoperative connection with said support.

References Cited in the file of this patent UNITED STATES PATENTS NumberName Date 1,177,503 Fellows Mar. 28, 1916 1,190,390 Fellows July 11,1916 2,221,827 Wildhaber Nov. 19, 1940' 2,616,336 Holstein Nov. 4, 1952FOREIGN PATENTS Number Country Date 552,348 Great Britain Apr. 2, 1943

